Optical fibers are in widespread use today as the information-carrying component of communications cables because of their large bandwidth capabilities and small size. However, they are mechanically fragile, exhibiting undesirable fracture under some tensile loads and degraded light transmission under some radial compressive loads due to a phenomena known as microbending loss. Optical fibers may be subjected to tensile loading during deployment and recovery operations of optical fiber cables. Radial compressive loads are typically exerted on the optical fibers as a result of hydrostatic water pressure in submarine applications. Radial compressive loads may also result from crush and impact from trawling, anchoring, and other ship-related activities. Optical fibers are also susceptible to a stress-accelerated chemical reaction between the glass material used in the optical fiber and water known as stress corrosion. Stress corrosion is a phenomena where small microcracks in the glass can increase in size which may adversely affect the mechanical and optical performance of the optical fiber cable. Optical losses in the fibers due to the diffusion of hydrogen into the interior of the optical fiber cable (where, for example, hydrogen may be produced from corrosion of metallic portions of the cable), represents another potential limitation on optical fiber cable performance.
Optical fiber cables often comprise one or more optical fibers, as well as non-optical elements such as strength members which bear the tensile and compressive loads placed on the cable while in operation. Some optical fiber cables may also employ electrically-conductive elements for carrying current to power repeaters, or for low-current signaling, for example. Optical fiber cables are typically joined together from a series of smaller segments to form long spans which may be used, for example, in transoceanic or other long-haul applications. The joint between the cable segments is often effectuated using what is conventionally known as a "jointbox." The jointbox, which is typically formed from high-strength materials including steel, houses the splices that provide a continuous optical path between individual optical fibers in the cable segments. In addition, the strength elements within the cable segments are typically joined using the jointbox to give the desired mechanical continuity to the optical fiber cable.
To protect the fragile optical fibers in the jointbox from environmental hazards (particularly, the damaging egress of water into the interior of the jointbox), and provide sufficient electrical insulation to any current-carrying elements that may be joined in the jointbox, some typical submarine optical fiber cables utilize a substantial polymer covering (often high-density polyethylene) that is molded directly around the jointbox in an "overmolding" process. While overmolding generally provides satisfactory results in some applications, it may not be cost-effective in other applications, because the required molding equipment is costly and the molding process is relatively slow which thereby restricts joining production rates. Moreover, in order to ensure proper integrity of the overmolded polymer covering, x-ray inspection is generally performed to detect voids and incomplete mold filling, among other defects, which represents additional equipment costs and adds to joint production time.